Feral Focus


Setting the scene

This scenario is set on a 45 000 hectare pastoral property near the South Australian town of Pinaroo. A large infestation of exotic prickly acacia (a noxious weed introduced from Southern Africa) has established on the property. As a result, the farmer is facing a number of problems including poisoning of live stock, a reduction in suitable grazing for his sheep and damage to their fleece and new born lambs. Over the years chemical sprays have reduced the spread of the prickly acacia but recently many plants are showing signs of resistance to the chemicals and are now starting to spread to adjoining properties. Bulldozing, ripping and reduction by burning are considered ineffective as it encourages rapid seed dispersal. The only animal known to graze on the prickly acacia is the giraffe. In Africa the prickly acacia is a much sought after meal for the giraffe who will often remove all of the leaves and effectively kill the plant. The farmer has applied for a permit to import 20 adult giraffes and five young to assist in the removal of prickly acacia.

What to do

Biosecurity Australia, a Government agency responsible for assessing the risk from allowing the import of pests, has sought comment from your business (Conservation Matters) on your views about the risk from permitting the import of giraffes into Australia.

  1. Research the biology of the giraffe to assess the potential for this animal to become an established pest.
  2. Use your findings to complete the pest risk assessment guide and create a score for each of the following sections:
    • Risk to public safety
    • Risk of establishing a wild population
    • Risk of becoming a pest
  3. Use the pest risk assessment table and calculate the probability of the giraffe becoming a pest in Australia if it escapes or is released from the pastoral property.
  4. Review information about the characteristics of successful pests.
  5. Prepare your response in the form of a detailed report to Biosecurity Australia.
    Include in your response:
    • the animal's threat status to Australia based on the completed risk assessment activity
    • the characteristics that would aid this animal in becoming a pest.
    • the economic consequences if this animal established a wild population
      • impact on primary industry
      • global industry
      • tourism industry
    • the cultural / social consequences if this animal established a wild population
      • safeguards, if any, that would be required to keep the public safe
      • the risk of the spread of disease
      • would public activity / outdoor recreation be affected?
    • the environmental consequences if this animal established a wild population
      • competition with native animals and birds
      • are there any critically endangered species that may be adversely affected?
      • is there a particular habitat that may be adversely affected.

Documents for download


Further reading

To gain a better understanding of the task at hand it is recommended that you read sections of the following:


Feral Fact

The most famous example of a pest animal being deliberately introduced to Australia is the cane toad.

In 1935 over one hundred toads were introduced to the cane fields of Gordonvale in far north Queensland in an attempt to control greyback cane beetles, a major pest to the sugar cane industry. Unfortunately it was soon realised that the cane toads had very little impact on cane beetle numbers. The beetles gathered on the upper parts of the sugar cane plant and were out of reach of the cane toads.

Due to excellent environmental conditions, a wide abundance of food and a lack of predators cane toad numbers rapidly increased and they soon started to spread. Cane toads are now found in Queensland, New South Wales and the Northern Territory and have recently made their way over the Western Australian border.

Cane toads are believed to compete for food, shelter and breeding sites with native frogs. They are extremely toxic to many animals such as native quolls and goannas who see them as a food source. The parotoid glands of the cane toad release toxin when the animal is provoked or squeezed as happens in the mouth of a predator. They can cause extreme irritation to humans if incorrectly handled and are regarded as a major nuisance by the public.

Did you know that Australia does not have any native toad species?